MCL

ActionsMedial Knee Anatomy

 

Primary valgus stability

- alone at 30o flexion

 

Secondary restraint to

- anterior translation

- to ER

 

Secondary medial stabilisers

 

Contribute in extension

 

Static

- ACL

- medial capsule 

- posterior oblique ligament

- medial meniscus

- PCL

 

Dynamic

- pes anserinus

- SM

 

Hughston JBJSA 1976

- MCL resists 50% of applied force        

- anterior & posterior capsule 25%

- ACL & PCL 25% (PCL>ACL)        

 

Seebacher's 3 layers of medial knee

 

1.  Superficial layer

- deep fascia / fascia lata

 

2.  Middle layer

- patella retinaculum

 

3.  Deep layer

- MCL, OPL (oblique popliteal ligament), SM (semimembranosus), capsule

 

Anatomy

 

Medial Knee Anatomy

 

Superficial portion MCL

- triangular in shape

- origin medial epicondyle distal to adductor tubercle

- inserts proximal medial tibia

- deep to pes anserinus

- anterior margin free

- posteriorly blends with capsule and is attached to medial meniscus

- posterior to MCL is OPL

 

Deep MCL

- deep to MCL

- meniscofemoral and meniscotibial ligaments

- capsular thickening

 

Semimembranosus

- attaches to the posteromedial corner of the tibia

- just below the joint line

- important dynamic stabiliser

 

Oblique Popliteal Ligament

 

Thickening of posteromedial capsule

- extension of semimembranosus

- originates from adductor tubercle

 

3 insertions

- superficial arm from femur to tibia posterior to MCL, running over SM to blend with pes

- tibial arm attaches to medial meniscus then to proximal tibia

- deep arm is an extension from SM to posterior capsule

 

Pes anserinus

 

Runs superficial to MCL

- 3 components

 

Say Grace before Tea

- Sartorius

- Gracilis

- Semitendinosus

 

The saphenous nerve and small saphenous vein emerge between sartorius and gracilis

 

Mechanism of injury

 

Valgus force coupled with ER injures 

OPL as well as MCL

 

Site of Injury

 

MCL usually tears at femoral end

- laxity more likely at tibial end

 

Associated Injuries

 

1.  ACL 

- grade II MCL has a 70% association with ACL

 

2.  Meniscus

- most common with combined MCL & ACL injury

- lateral meniscus more common 3:1 with ACL tear 

- O'Donaghue triad rare

- Shellbourne 163 cases >50% had lateral meniscus tear

 

Examination

 

Discreet tenderness at femoral or tibial insertion of MCL

 

Tested in extension & 30° flexion

 

Remember to test both sides

- compare to contralateral side

 

Lax in extension

- tear to secondary constraint

- ACL / PCL / medial capsule

 

Grading

 

Grade 1 / Laxity in flexion 3-5mm

 

Indicates mild sprain of MCL

- up to 1/3 torn

- usually no laxity in extension

 

Grade 2 / Laxity in flexion 5-10mm

 

Indicates moderate sprain of MCL

- 1/3 to 2/3 torn

- usually no laxity in extension

 

Grade 3 / Laxity in flexion >10mm

 

Indicates complete disruption of MCL

- no endpoint

 

Usually lax in extension

- indicates disruption to secondary restraints

 

Also may have

- ACL laxity

- OPL instability / positive anterior draw in ER

- PCL laxity 

 

X-ray

 

Usually normal in acute injury

 

Bony Avulsion

 

MCL Bony Avulsion

 

Pellegrini-Stieda Lesion 

- calcification at insertion of femoral MCL

- indicative of chronic injury

- can rarely be symptomatic

- requires excision of calcification +/- reconstruction MCL if needed

 

Pellegrini Steida Lesion

 

MRI 

 

Acute

 

1.  Femoral injury

 

MRI Grade 3 Femoral Avulsion MCLMCL acute grade 3 Femur MRI

 

2.  Tibial avulsion

- can be flipped above pes

- will not heal

- will require surgery

 

3.  Midsubstance

- rare

 

MCL Midsubstance Tear MRI 1MCL Midsubstance Tear MRI 2

 

Chronic

 

See thickening of ligament

 

MCL Chronic Femoral Thickening on MRIMCL Chronic Femoral Thickening

 

Arthroscopy

 

Will see lift off of the medial meniscus

 

Arthroscopic Lift off of medial meniscus in MCL injury

 

Management

 

Non operative Management

 

Indication

- isolated injury

- no ACL / meniscal injury

- no displaced tibial avulsion

 

ACL + MCL

 

Delayed ACL reconstruction

 

Manage MCL non operatively as per below

- delayed ACL reconstruction if required

 

Zaffagnini et al JBJS Br 2011

- 3 year follow up of ACL reconstruction with grade II MCL treated nonop

- no impact on AP instability at 3 year follow up

 

Immediate ACL reconstruction

 

Halinen et al Am J Sports Med 2006

- RCT of acute ACL reconstruction in patients with grade 3 MCL

- operative v non operative management of MCL

- no difference in the two groups

 

Millett et al J Knee Surg 2004

- early ACL reconstruction with non operative management MCL in 18 patients

- at 2 year follow up no graft failure or valgus instability

 

Algorithm

 

Grade 1

 

Control pain & inflammation

- RICE 

- analgesia

- weight bear as tolerated

- ROM exercises

- muscle-strengthening exercises once FROM

 

Grade 2

 

As above plus hinge brace for 2 - 4 weeks

A.  Protect against valgus stress

B.  Full range if proximal MCL tear

C.  15° extension block if distal tear MCL or POL tear as well

 

Grade 3


Aim

- prevent full extension

 

6/52 in ROM hinged brace

- 30-60o for 2/52

- 30-90o for 2/52

- full range for 2/52

 

Results

 

Marshall et al Clin Orthop 1978

- demonstrated equal results with operative v non operative treatment of MCL

 

Operative Management

 

Indications

- displaced tibial avulsion

- displaced bony femoral avulsion

- chronic MCL instability

- MCL instability after ACL reconstruction

 

Bony MCL Avulsion

 

Elevate VMO

- repair with staples

 

MCL Bony Avulsion IntraopMCL Bony Avulsion Intraop 2

 

MCL Bony Avulsion ORIF APMCL Bony Avulsion ORIF Lateral

 

Stener Lesion

 

MCL Stener Lesion

 

Chronic MCL reconstruction

 

1.  Distal MCL MCL Advancement

- if detached from tibia

- double row repair (as for rotator cuff) increases surface area for healing

 

Distal Tibial Advancement 1Distal Tibial Advancement 2

 

MCL Tibial AvulsionMCL Tibial Avulsion Double Row Repair

 

2.  Proximal MCL Advancement

 

Proximal MCL Advancemetn 1Proximal MCL Advancement 2Proximal MCL Advancement 3

 

Indications

- proximal laxity

 

Options

A.  3 x figure 8 stitches to imbricate MCL and POL proximally

- tie over screw

- tighten MCL and POL

 

B.  Detach MCL

- 2 x distal suture anchors, pass sutures through tendon

- proximal staple

 

MCL Reconstruction APMCL Reconstruction Lateral

 

MCL Advancement APMCL Advancement Lateral

 

3.  Reconstruction of MCL and posteromedial complex (OPL / SM)

 

A.  Semitendinosus

 

MCL Reconstruction 2 Incision

 

Technique

- left attached distally

- re-routed more posteriorly on tibia around screw and soft tissue washer

- to medial epicondyle / isometric centre

- line of intersection of posterior femoral condyle and blumensaats

- insert wire and test isometricity in flexion / extension

- drill hole and fixate with RCI screw into blind loop of tendon

- return to tibia posteriorly to reconstruct OPL / secure with anchors and supplementary screw post

 

MCL Isometric PointMCL Reconstruction Tibial Screw Post

 

Lind et al Am J Sports Med 2009

- 50 patients followed up for minimum 2 years

- isolated instability / ACL and MCL / multiligament knee

- 98% had medial stability of normal or nearly normal

 

Kim et al JBJS Br 2006

- semitendinosus left attached distally

- reconstruction of MCL and OPL

- medial joint line opening within 2 mm in 22/24 knees

 

B.  Allograft

- doubled tibialis anterior

- tendoachilles allograft - bone block in medial femoral epicondyle

 

Marx et al CORR 2012

- 14 cases treated with tendoachilles

- good results in all cases

 

4.  Hughston Procedure

 

Technique

- advance femoral attachment of MCL

- advance femoral attachment of OPL

- stretch OPL anteriorly onto MCL

- reef SM forward to decrease slack

 

Surgical Approach to Medial Knee

 

Position

- knee flexed to 90o, over bolster

- tourniquet

- sandbag under hip

 

Incision

- hockey stick medial incision

- halfway between borders of tibia

- extends proximally to adductor tubercle

- distally to pes

 

Superficial dissection

- protect the saphenous nerve and small saphenous vein

- emerges from between sartorius and gracilis

- divide fascia over pes, reflect downwards

- divide medial patella retinaculum from VMO down to the pes

 

Deep dissection

- expose MCL running down to tibia under pes

- oblique popliteal ligament and SM are posterior to it

- can expose posterior capsule by carefully reflecting medial gastrocnemius posteriorly

- enter to joint if needed between posterior border of MCL and OPL

- identify proximal MCL attachment by elevating V medialis